Process of separation of ore materials



Patented Mar. 17, 1942 UNITED "STATES PATENT OFFICE 2,257,910

Robert B. Booth, Springdale, Conn, assignor to American CyanamidCompany, New York, N. Y., a corporation of Maine No Drawing. ApplicationMarch 3, 1939,

- Serial No. 259,577

10 cl ims. This invention relates to the gravity separation of materialsin liquid media, particularly in Many processes involve the separationby dif- 1 ferences in specific gravity in aqueous and other media.Usually the desired result is to obtain separation by difierentialsettling; in other cases it is desired to cause one constituent to sinkand In many cases where slimy the other to "rise. material is present,clean separation is prevented and in other cases, the slimy material mayfloc and acquire a characteristic at variance with its normalcharacteristics. Thus, for example, when very fine materials which wouldnormally remain in suspension or float oil in specific gravityseparations floc together, they acquire the characteristics oflargerparticles and either tend to sink or to deposit themselveson surfaces ofapparatus in which tlieyare being treated.

According to the present invention, a new class of dispersants, namely,dyes having solubilizing groups, especially sulfonic groups, is used.While dyes containing solubilizing groups are in general operative withcertain materials, there is a great difference in eiiectiveness betweendifferent solubilized dyes. I have found that four coloring matters giveexcellent results and two of these materials are outstanding. The fourmaterials referred to are solubilized Nigrosine (C. I. 865),

. an earth color sold in the trade as Sap Brown,

, matter in the fifth edition of A Text-Book of Paper Making, by Crossand Bevan, distributed by Chemical Publishing Company of N. Y., Inc. Adefinition of Sap Brown" is found on page 272 of the above text-book.

forming compounds in boiler water, and the increase of fluidity ormobility of suspensions such as sludges.

The reason why invention possess such extreme efliciency as dispersantsis not as yet determined and the present invention is not limited to anyparticular theory of action,

While the dispersing property is p'ossessed' to a greater or less degreeby the various dyes containing sulfonic or other solubilizing groups,the

degree to which this power is possessed will vary greatly and the fourcolors referred to are markedly superior to the other colors which havebeen tested and this is particularly true of Nigrosine and Sap Brown.The effectiveness of a particular dye will also vary with the particularmaterial although, in general, in no case' have we found any othercolors to be superior to Nigrosine or Sap Brown with any material.

The dispersing agents of the present invention may be used alone or theymay be used with other known dispersants such as lignin sulfonatesdescribed in connection with the depression of carbon in the BreerwoodPatent No. 2,130,574 dated September 20, 1938, dextrin described in'myPatent No..2,l45,206 dated January 24, 1939, and the like. Thisadvantage of the present invention greatly adds to its flexibility andto its field of usefulness. Every material presents a particular problemand the best dispersant to use, whether a single one or a mixture,

Most of the operations involving the new dispersants belong to the'field of ore dressing, such as ordinary classification, desliming,jigging,

ftabling, amalgamation, and the like. The invention is, however, notlimited to operations involved in ore dressing and the new dispersantsare alsouseful in other industries such as, for

example, in the dispersion ofclay and silt in the drilling of oil wells,the dispersion of scalematerials to be treated.

It should be understood that the present in-- vention deals withdispersion problems outside of a froth flotation cell. I do not claimhere the use of solubilized dyes in froth flotation, this being thesubject matter of my copending application, Serial No. 216,291 filedJune 28, 1938.

The invention will be described in greater detail in conjunction withthe following'specific examples which illustrate the application of theinvention to various processes and with various materials. Theseexamples are illustrative only. SAND SLIME SEPARATIONS Exam: 1 AnAfrican ore, containing gold and slim limenite, sericite, and quartz andassaying about 0.20 oz. Au/ton, 0.02% S, 6.51% Fe, and 79.72% insoluble,was ground to minus mesh, 71% minus 325 mesh. The resulting pulpcontained alarge amount-of slimy material (slimes) which,

the soluble dyes of the present.

of sands settling out in the first five minutes after treatment with thedyes are given in Table 1. Volume readings were taken at thirtysecondintervals.

The results of the tests with the dyes were compared with those obtainedin a control test in which no dispersing agent was used and with thoseobtained in separate tests with 1.0 lb./ton sodium carbonate, calciumlignin Sulfonate, sodium lignin sulfonate, and sodium silicate. I

All these tests were carried out at a pH of 5.3,

the natural pH of the pulp.

\- Nigrosine s r s-99 9MB:-

5.01bs.lton Sap Brown, 0.5 lb.lton H28 4 5.0 lbs/ton 0.5 1b./ton H180 Noseparation of sands from slimes was noted in control tests in which nodye was added but 0.5 lb./ton CaO, 4.0 lbs/ton CaO and 0.5 lb./t'onH2804, respectively.

On this same pulp, combinations of the dyes and certain alkalies wereefiective dispersants Trable I as indicated by the data in Table III.

.VoIume (00.) of sands Table HI Time, minutes 1 01b./ton lbJton vmme(cc') of Sands Sap Brown Nigrosine Time, minutes 0.75 lb./ton0.751b./ton 0.5 20 25 NasOOg, 0.50 Na:0O.\, 0.50 l. lb./ton Saplb./tonN1gro- 0- 50 4s 70 68 Brown sine 13% 138 3.0: 118 115 25 3.5. 123125 55 4.0 133 75 80 4.5'. 145 145 90 100 50 10s 11s 1 0 150 120 130 130140 No separation'of sands from slimes was noted {2% Q in control testsin which no dye was added, and 150 105 also in separate tests with 1,01b./ton sodium carbonate, calcium lignin sulionate. sodium ligninsulfonate, and sodium silicate. These latter comlg l g-lg g pounds aredispersants now commonly used in fi tgl'gi lb.7iaonl -ligrometallurgicalpractice. 40 Brown s After the addition of 0.5 1b./ton sulfuric acid 1(pH 4.9), or'0.5 lb./ton CaO (pH 6.4), or 4.0 g lbs/ton CaO (pH 9.0) tothe pulp, these dyes t1 so so were effective in dispersing the slimesand al- ;:g :22 lowing the. sands to settle as is shown by the 5; 12s12s data in Table II. Y Y a. 1g 3% Table II 1: 152 d 5 100 100 Volume(00.) 0f sands o EXAMPLE 2 Time, inu l -l n g g Similar tests with dyeswere conducted on a v 05 1b./ton file $3 slimy ore from California,containing free gold, CB0 9 0 pyrite, clay and quartz and assaying about0.10 oz./ton Au and 0.07% S. Samples ,were ground 3 :3 g? 55 to 1% on 65mesh, 67% minus 200 mesh a 1.51""IIIIIIIIII 62 7g suspended in one-litergraduated cylinders at a 2:2- g2 I pulp density of about/40% solids. Thevolumes 3.0: 05 125; of sands settling out in the first five minutes in3'8 33 i 3 tests with dyes and in a control test without i ZIIIIIIIZI130 58 dye e given in Table Table IV lg b l s g n Volume (00.) of sandssw a t n. 'r' t 4.0 b'sJton lglbalton mm as 0151mm 0151mm 0.5mm: 920 C00Nigrosine SapBrown SunYcilow 05 25 a0 0,5 .50 50 55 1.0... 50 65 1,0 100100 116 1.5- 70 7s 70 1.5. 138 140 2.0. so 05 2.0. 108 110 102 2.5- 1052.5. 190 .100 218 3.0... 120 30 ms 210 215' 3.5. 130 0.5- 222 225 2504.0- I 142 4.0. m5 215 202 4.5- 148 4.5- 245 245 270. 6.0 100 152 755.0. 252 252 280 No separation of sands and slimes was noted incontroltests in which no dye was added. I

A similar test of this California ore was conducted at a pulp density ofabout 50% 'solids. 0.75 1b./ton oi sulfonated beta naphthol tar was usedas the dispersing agent. The results of this test are given in'TableIV-A.

of dyes it was possible to disperse the slimes to pct-containing themajor portion of the gold could be obtained and to' separate from such aproduct over 26% of theore by weight as slimes containing a relativelysmall portion of Table IV-A t "d I JIGGING v1 1 v I o gfg o Examnn 3 V"3 1 33.39333: Samples of about 600 g. of an ore from the naphthol tarPhilippine Islands, containing free gold (35 the dyes and the sulfonatedbeta-naphthol tar I were effective dispersants for the slimes in thesemesh-600 mesh in particle size), galena, pyrite,

0. so chalcopyrite, sphalerite, 'limonite. quartz, and $8 calcite andassaying about 0.45-0.55 oz./ton Au, 2. was. ground .at a pulp densityof 67% solids to minus 100 mesh, 58% minus 325 mesh. diluted 2. gggtoabout 50 solids, then treated with various dyes 1 m 20 in a series ofseparate tests, and subjected to a 280 jigging operation in a laboratoryjig.

A control test was similarly conducted except that no dyes were used.The results of these parison of gold recoveries in the jig concentratesin tests with and without dyes shows that'an increase in recovery ofover was obtained in the tests employing the dyes.

Table VI Feed Jig concentrate Jig tailing Test N o.

Gs 0z./ton Wt., per- 0z./ton Percent Wt., pcr- 0z./ton Percent Au centAu Au rocov. cent Au Au recov.

Test 4'.- Control test; no dyes used. Test 5.-l.0 lbJton Sap Brown.

' Test 6.1'.0lb./ton Nigrosins.

ores/and aided in the separation of sands and slimes. 1

In another series of tests on the above-described California gold ore,separate samples were treated with 0.15 lb./ton Nigrosine or Sap Brownat a pulp density of 40% solids in oneliter graduated cylinders and thenallowed to settle for 22 minutes. relatively coarse-grained materialsettled out cleanly. The major portion of the slimes was contained inthe supernatant 610 cc. of pulp and these slimes were readily drawn offfrom the sands. Both products were assayed for gold.

In a control test similarly conducted except that no dyes were used,only a relatively small quantity of sands settled out, and the separa-'tion was not clean, since the material which had settled out contained alarge quantity of slimes.

In this time, 390 cc. of 5 The jigging operations are described above inconnection with the use of a solubilized color in the absence'ofinorganic dispersing media. Similar excellent results are obtained whenthe. color is mixed with some inorganic dispersing medium such ascaustic soda or sodium carbonate.

TABLING ExAmLs 4 a tabling operation on a laboratory Wilfley table toproduce a concentrate, middling, and tailing which-were assayed forsulfur. A control test was conducted similarly except that no dye wasused. The results of these tests are summarized The results of thisseries of tests are given in in Table V11. A marked increase in pyritere- Table V. covery in the table concentrate was noted in the Table VFeed h slimes I Bands 7 Test No. 1 s

Gs Oz./ton GS Wt.. 0z./ton Total Au, Gs Wt., QzJton Total Au,

' Au percent Au. percent percent a u percent Test !.-Control test: nodye used.

Tea! .'0.l5 lb.lton Nigrosine. Test 8.0.15lb./t0n Sap Brown.

The results of these tests show that by the use jigging tests arepresented in Table VI. A com--- Brown and Sun Yellow and then subjectedto Test N0.

tests employing the dyes as is indicated by the sulfur recovery.

the colors used inorganic materials. The fact that the colors oi TableVII I Feed Concentrate Middling Tailing Test as Assay Weight, AssayReoov. Weight, 'Assay Becov. Weight, Assay Recov.

' Percent 8 Percent Percent 8 Percent 8 Percent Percent 8 Percent 8Percent Percent 8 Percent S Test 7.Control test: no dye used. Tut 8.0.5lb./ton Nigrosine.

Tut 9.-0.5 lbJton Bap Brown? Teal 10.0.5 lb./ton Sun Yellow.

The tabling operations are described above in connection with the use oia solubilized color in the absence of inorganic dispersing media.Similar excellent results are obtained when the color is mixed with someinorganic dispersing medium such as caustic soda or sodium carbonate.

AMALGAMATIION Exssrrnn A gold ore from South Africa containing pyrite.magnetite, iron oxides; chalcopyrite, quartz and carbonaceous materialand assaying about 0.12- 0.14 ozJton Au, 4.38% Fe, 2.29% S, 0.54% C; and

86.4% insoluble, was ground to about 5% on 65 Table VIII Mgs. Au-Percent total Au Iniocd .InHg Intail Intel] Ta: IL-Control test; no SapBrown used. Tut l2.l.0 lb. lton Sap Brown.

The amalgamating operations are described color in the absence ofinorganic dispersing media. Similar excellent results are obtained whenthe color is mixed with some inorganic dispersing medium such as causticsoda or sodium carbonate.

It will be noted that the presentinvention is quite generally applicableto various dispersing and allied problems and it is applicable in mediawhich have 'not been altered from their natural state and also pulpswhich have been rendered acid or alkaline by the addition of suitableconditioning reagents. The fact that the dispersants of the presentinvention can be used with certain the presentinvention may be used bothin combination with inorganic dispersants and without them gives thepresent invention an extraordi nary flexibility, permitting it to beadapted to problems of the most varying character.

It is an advantage of the present invention that the improvementsobtained by the use of solu-, bilized colors are not limited to theuse-of any particular ore-dressing procedure. For example,

itmay be found advisable in certain cases to add the dispersant to thegrifiding'circuit; in other cases, the-reagent may be used moreefliciently when added to the classifier or some other point in thecircuit. I

What I claim is:

1. A method 01' separation oipre materials by diflerential settlingwhich comprises subjectingv an aqueous suspension containing slimy andcoarser ore materials including gangue slime to difierential settling inthe presence of a coloring matter included in the group consisting ofsulfonated Nigrosine, Sap Brown, sulionated beta- 4 above in connectionwith the use of a solubilized naphtholstill tars and Sun Yellow.

2. A method of separation of-ore materials by diilerential settlingwhich comprises subjecting an aqueous suspension containing slimy andcoarser ore materials including gangue slime to diflerential settling inthe presence or sulionated Nigrosine. r

3. A method of separation of ore materials by differential settlingwhich comprises subjecting an aqueous suspension containing slimy andcoarser orematerials including gangue slime'to differential settling inthe presence of Sap Brown.

4. A method of separation of ore materials by I differential settlingwhich compris subjecting known inorganic dispersants such as causticsoda.

sodium carbonate, and the like, is an important advantage because insome cases the extreme cheapness of th inorganic material permits alower overall cost by using both the inorganic material and the colorsof the present invention.

As many operations have to be carried out at very low cost, the savingsthus effected are frequently an aqueous suspension containing slimy anddiiieiential settling in the presence of sulionated residue frombeta-naphthol stills. 5. A method of separating ore materials bydifl'erential settling which comprises subjecting an aqueous pulp of orematerials containin gangue slimes to stratiiication by discontinuousacceleration of the tabling-and jigging type, the stratiflcatlon takingplace in the presence of a coloring matter included in the groupconsisting of .suli'onated Nigrosine, Sap Brown, sulionatedbeta-naphthol still tarsand Sun Yellow.

6. A method of separating ore materials by diflerential settling whichcomprises subjecting an aqueouspulp' of ore materials containing gangueshines to stratiiication by discontinuous acceleration of the tablingand jigging type. the

stratiflcation taking place in the presence of sulfonated Nigrosine.

*7. Amethod of separating ore materials by dififerential settling whichcomprises subjecting an do not have to be applied with difierentiaisettling which comprises subjecting an aqueous pulp of ore materialscontaining gangue slimes to stratification by discontinuous accelerationof the tabling and jigging type, the

stratification taking place in the presence of sulfonated residue frombeta-naphthol stills.

9. A method according to claim 1 in which the operation is effectedinthe presence of an alkaline inorganic dispersing medium.

10. A method according to claim 5 in which the operation is effected inthe presence 01' an alkaline inorganic dispersing medium.

ROBERT B. BOOTH.

